I condider myself to have a very good understanding of Active Directory and I am aware of the obvious benefits of having more than one domain controller in a domain.

My question is basically this. When one domain controller is not available, how does a PC in the domain know to revert to another domain controller?

Thanks for any help.

  • 1
    What does nslookup your.domain return? :) – jscott Dec 10 '12 at 19:39
  • @jscott, thanks for the quick reply. It simply returns the IP address of the current domain controller/dns server (My current network only has a single domain controller). My question is simply curiosity based and not practical based. – slickboy Dec 10 '12 at 19:42
  • 2
    Here you go, the DC Locator process: blogs.technet.com/b/arnaud_jumelet/archive/2010/07/05/… – joeqwerty Dec 10 '12 at 19:53
  • @joeqwerty Link answers suck but that is by far the best answer to this question. I'd post it anyway. – Brent Pabst Dec 10 '12 at 19:55
  • I was being lazy so I posted the link as a comment instead of a full answer with the link included. It looks like @Greg Askew got it. – joeqwerty Dec 10 '12 at 20:00

It's known as the DC Locator process.


How DNS Support for Active Directory Works

DNS returns a list of DC's sorted by priority and weight. The client attempts to communicate with a DC, and moves to the next DC in the list if a response is not received in a brief period. Ping the Candidate Domain Controllers for "Liveness" and Capability Verification Using LDAP Ping Mechanism

If the client cannot locate a DC in it's site, or if the client is not in a site, it will attempt to contact any domain controller in the domain.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.